Fiber optic networks are becoming increasingly commonplace in telecommunications applications due to their increased bandwidth and distance capabilities relative to copper networks. Compared to copper systems, however, fiber optic cables and connections are well-known for their more critical and difficult terminations. For example, the alignment between abutted glass cores within a fiber optic interface is crucial to the performance of the connection.
Field installation of standard “pot and polish” fiber optic connectors is extremely labor- and expertise-intensive. The installer is required to prepare a fiber end, glue the fiber end into the connector, cleave the excess fiber from the endface of the connector, and polish the endface of the connector to obtain the optimum geometry for optical performance. Endface polishing is a difficult and time-consuming step, particularly when using singlemode fiber, and it is best performed by an automated polishing machine. Automated polishing machines are often large and expensive, however, making them impractical for field use.
Fiber pigtail connectors were designed to eliminate the need for these lengthy steps. A pigtail connector is prepared at the factory with a length of fiber. In the factory, precise polishing machines can be used to achieve a consistent polish. The endfaces can be inspected at the factory to ensure correct endface geometry for optimum performance. In the field, the installer would have to splice a length of fiber to a cable by means of a fusion splicing machine. This eliminates much of the labor time, but it requires the installer to purchase a fusion splicing machine and protective sleeve, which are expensive. This type of connector would require extra storage space for protection of the fusion splice.
Fiber stub connectors were designed to eliminate the need for expensive fusion splicing equipment, splice protection, and lengthy termination steps. The stub connector employs a short fiber stub that is spliced to the field fiber within the connector. Stub connectors typically require a crimp to either activate the splice or retain the field fiber, or both. The crimping operation, however, whether occurring at the interface point or at some other point to retain the field fiber, may have a tendency to pull the field fiber and stub fiber apart, or otherwise damage the signal-passing function of the interface. If the connection is found to be poor after the crimping occurs, the connector must be cut off because crimping is generally an irreversible operation. Thus, the connector and a length of fiber optic cable are wasted, and a new connector must then be terminated. This waste can be expensive and time-consuming, and can be an annoyance to the installer by delaying network activation. A reusable stub connector would thus be desirable.